Objective: In this paper

the rheology and release kinetics of Chuanqi ophthalmic microemulsion in situ gel were investigated. Method: The fluid properties and linear viscoelastic regions of this preparation were investigated by MCR 102 rheometer.The release kinetics of Chuanqi ophthalmic microemulsion in situ gel was evaluated by modified Franz diffusion cell method

the ligustrazine and ligustilide were selected as the indictors

and semi-permeable membrane was used as a barrier. Result: Chuanqi ophthalmic microemulsion in situ gel was a pseudoplastic fluid and it had a linear viscoelastic region.The range of the linear viscoelastic region was 0-302.74 Pa while shear stress as an indicator.The range of the linear viscoelastic region was 0-7.45% while strain as an indicator.At the critical point

the storage modulus(G')=the loss modulus(G")=2 976.60 Pa

critical shear force was 302.74 Pa and critical strain was 7.45%.The release amount of ligustrazine was 33.71 μg within 8 h and its average cumulative release rate was 90.08%

the release kinetics followed Higuchi equation.The release amount of ligustilide was 68.46 μg within 8 h

its release rate was 84.32%

and its release kinetics followed zero-order kinetics equation. Conclusion: Chuanqi ophthalmic microemulsion in situ gel has excellent viscoelasticity

and the deformation is reversible in a certain range.The release kinetics of ligustrazine is result from synergistic effect of its physicochemical properties and matrix skeleton

but the release kinetics of ligustilide is mainly affected by its physicochemical properties.